Sanofi (SAN), unlike rivals such as Merck & Co., won’t push hard to find an Alzheimer’s treatment because the science isn’t advanced enough to justify the costs to develop a drug, Chief Executive Officer Chris Viehbacher said. Sanofi, the French drugmaker that has gained 42 percent in the past year, “definitely” won’t commit major resources seeking to discover an Alzheimer’s therapy, Viehbacher said, in contrast to the strategy announced by rivals such as Merck, Eli Lilly & Co. (LLY), Johnson & Johnson (JNJ) and Pfizer Inc. (PFE) Drug companies are vying to be the first with an effective drug for the mind-robbing condition. The most common of dementia illnesses, it’s expected to affect 65 million people worldwide by 2030 and a treatment that can slow the disease’s progress promises tens of billions of dollars in sales. There have been 101 failures since 1998, according to the Pharmaceutical Research & Manufacturers of America, including setbacks last year in late-stage clinical trials by Pfizer, J&J and Elan Corp.